Micro-electrophoresis apparatus



May 2, 1967 s, RAYMOND 3,317,417

MICRO-ELECTROPHORESIS APPARATUS Filed ont. ze, 196:2

FIGn I F|G.5

INVENTOR. SAMUEL RAYMOND A TTORNEYS United States Patent C) 3,317,417 MICRO-ELECTROPHORESIS APPARATUS Samuel Raymond, 538 Walnut Lane, Swarthmore, Pa. 19081 Filed Oct. 26, 1962, Ser. No. 233,352 4 Claims. (Cl. 2114-299) This invention relates to improvements in electrophoresis apparatus, and particularly to a micro-electrophoresis unit for practicing immuno-electrophoresis and including a self contained power supply.

Electrophoresis, generally, relates to the separation of a complex substance into its component fractions by a procedure based upon the migration or mobility of electrically charged fractions in a direct current electric field. With an electric eld developed between two spaced electrodes and a substance placed therein, the variously charged components or constituents of the substance move or migrate toward the respective electrodes of the opposite charge and the respective components will move with different mobilities. While the field is established by the D.C. current flowing, the components move continuously at different speeds and thus separate into different groups. The separation action may take place on a sheet of absorbent material such as filter paper wetted with `a buffer solution, or on a permeable gel. Each component separated by the electrophoresis procedure is subject to qualitative and quantitative analysis.

Apparatus for accomplishing electrophoresis are obviously useful tools in laboratory analysis of various substances including proteins such as albumin, enzymes, hemoglobin, carbohydrates, blood serum, etc., as well as various inorganic ions. Electrophoresis apparatus are presently known in the art, for example see the apparatus disclosed in the patents to Ressler 2,843,540 issued July l5, 1958, and reissued Dec. 15, 1960, as Re. 24,752, Sharpsteen 2,962,426 issued Nov. 29, 1960, and my Patent 3,047,489 issued July 31, 1962. However, the known electrophoresis units leave much room for improvement in certain respects.

In the known electrophoresis units, electrodes conventionally extend across buffer solution tanks and these electrodes are connected to a separate power supply unit which is adjustable and quite expensive. Typically, the electrophoresis apparatus and the power supply are two separate items which must be purchased separately and then connected together. The usual power supply itself is quite large, as is the electrophoresis unit. Since these units are used in laboratories and hospitals where space 'requirements are critical and cost is a consideration, the advantages in reducing the size and cost of the entire apparatus and power supply are apparent. It is the object of this invention not only to reduce the size of an electrophoresis apparatus and a power supply unit therefor but also to combine the power supply with the electrophoresis apparatus, thus making a single miniaturized combination electrophoresis apparatus and power supply which can be operated by merely connecting a conventional electric cord and plug to a convenient source of A.C.

Also, in the known electrophoresis apparatus electrolytic contact between buffer solution and the electrophoresis supporting medium is accomplished by wicks or other separate devices for capillary attraction. It would be desirable to find a way of accomplishing this electrolytic connection while dispensing with the details of providing a wick or the like. It is a further object of this invention to provide a novel arrangement for making electrolytic connection vbetween the buffer solution in the tank and an electrophoresis supporting medium positioned above the butler solution.

In electrophoresis units of the type under consideration, the electrode positioned in a butter solution containing 3,317,417 Patented May 2, 1967 ICC tank should be as far as possible away from the point of electrolytic contact with the electrophoresis zone supporting medium. In conventional apparatus this is accomplished by having the electrodes positioned at the opposite corner of the tank from the place where the wick enters the buffer solution containing tank. It is the object of this invention to provide a unique positioning of the electrodes within the tank while still maintaining a maximum distance between the electrodes and the electrophoresis supporting medium but at the same time reducing the overall size of the unit Iby arranging the electrodes back to back and extending the electrophoresis supporting medium outward above the top of the electrodes.

A further feature of this invention is a safe power supply circuit potted integrally within the electrophoresis apparatus.

Other objects of this invention will be pointed out in the following detailed description and claims and illustrated in the accompanying drawings which disclose, by way of example, the principle of this invention and the best m-ode which has been contemplated of applying that principle.

In the drawings:

FIG. 1 is a diagrammatic view of one type of prior art electrophoresis apparatus.

FIG. 2 is a sectional front elevational view of the electrophoresis apparatus of this invention.

FIG. 3 is a top plan view of the electrophoresis apparatus with the top removed for the sake of clarity.

FIG. 4 is a diagrammatical circuit diagram of one embodiment of a power supply circuit to be used in the electrophoresis apparatus.

FIG. 5 is a circuit diagram of another embodiment of a power supply circuit for the electrophoresis apparatus.

Referring to the drawings, FIG. 1 represents a typical prior art electrophoresis apparatus 10. The electrophoresis apparatus 10 is provided with two separate buffer solution containing tanks 12 and 14. Between the tanks and above the top of the buffer solution lever is a support 16 for an electrophoresis supporting medium. The electrophoresis supporting medium whether a gel, paper, or the like, would be positioned on the support 16 and is electrolytically connected to the buffer solution by means of wicks 19 and 20. A separate relatively large, expensive, adjustable power supply unit 22 would be provided for plugging into a conventional source of A.C. and by suitable adjustments the power supply may provide a particular selected D.C. potential at the output thereof. The power supply 22 is electrically connected to electrodes 23 and 24, which may be platinum wires extending across the buffer solution containing tanks 14 and 12. Typically, the electrodes would be positioned as far as possible distant from the wicks 19, 20, for example in a far corner of the tank.

As can be seen from an analysis of the representative prior art shown in FIG. l, the relatively large area required for the electrophoresis supporting medium 18 together with the requirement that the electrodes should be at the opposite ends of the buffer solution containing tanks from the wicks 19 and 20, causes the bulfer solution containing tanks 12 and 14 to be relatively widely separated. Also, the power supply 22 is required to be an entirely separate and relatively expensive unit which in itself takes considerable room. The wicks 19 and 20 must Ibe separately positioned when the supporting plate 16 is positioned on the apparatus to be sure the electrolytic connections are intact. Of course, in use, after the fractions have electrolytically separated, the plate 16 is removed from the vresistor 74 is connected across the rectifier bridge and these output 26 including end walls 27 and 28, side walls 29 and 30, and separate bottom portions 31 and 32 which do not quite meet, leaving a gap 33 across the bottom of the container. An inverted U-shaped central dividing wall 34 is secured to the edges of the bottom portions 31 and 32 to enclose the gap 33 and leave a U-shaped portion for insertion of a power supply. The container may conveniently be constructed of Lucite or similar machinable and electrically inert plastic.

The top of the unit may be closed with a cover 36 provided with guides 37 for inserting the top and a handle 38. The cover will assist in preventing some evaporation from the unit.

Within the unit are blocks 40 and 41 of absorbent material such as cellulose sponge or the like. At the top edge facing corner of the blocks there is a cut-out corner step 42 on block 40 and 43 on block 41. This step forms a support for a plate 44. Plate 44 is removable and in turn supports the electrophoresis supporting medium 45 which may be gel, starch, paper or the like.

Within each side of the container adjacent the central dividing wall 34 there are effectively formed tanks 47 and 49 for containing buffer solution 48. The buffer solution will be absorbed in the sponge-like blocks 40 and 41 and will wet the entire blocks thus making electrolytic contact at the steps 42 and 43 with the electrophoresis supporting medium 45. This arrangement eliminates the need for wicks and the like.

Within the space in the inverted U-shaped central dividing wall 34 there is positioned a power supply package 50. This power supply pack is potted and hermetically sealed and has a pair of electrodes 52 and 53 extending therefrom through the side of the U-shaped dividing Wall 34. These electrodes may be of platinum wire or the like and extend mostly along adjacent the sides of the U-shaped dividing wall as shown in FIG. 3. Because the electrodes 52 and 53 are back to back, the plate 44 for the electrophoresis supporting medium can extend toward the end walls 27 and 28, thus providing the long path through the buffer solution from the electrode without increasing the size of the apparatus. A conventional electric cord 54 having the usual electric conductors 55 and S6 therein and a conventional plug 57 is adapted to be plugged into an ordinary 110 v. 60-cycle A.C. supply and the circuit within the power supply package 50 provides the requisite and adequate D.C. potential for electrophoresis.

Within the power package 50 there is a suitable miniaturized power supply which can conveniently be accommodated in the space within central dividing wall 34. In the embodiment illustrated in FIG. 4 there is shown a stepdown transformer 58 having a primary coil 59 adapted to be connected to an A.C. source and a secondary coil 60 connected to a full wave rectifier. In the outputs of the ends of the secondary coil 60 are unidirectional current conducting devices such as diodes or rectifiers 61 and 62 connected to the positive electrode 52. The secondary is tapped at 63 directly to the negative electrode 53. A signal lamp 64 across the A.C. line 55, 56 will indicate when the device is in operation.

With the plug 57 plugged in the conventional A.C. will be stepped down and rectified and fed to the electrodes 52 and 53 for providing a D.C. potential for accomplishing the electrophoresis. Because the electrodes 52 and 53 are separated from ground by the transformer 58 it would be impossible to get a heavy shock. Any other suitable miniaturized power supply could also be utilized, so long as it could be accommodated Within central dividing wall 34. For example, as shown in FIG. 5, a resistor 70 could be used to drop the voltage from a conventional 60 cycle 11G-120 volt A.C. power source. The pilot light 64 is connected across the source to indicate the presence of A.C. power. A full wave, 4 diode, rectifier bridge 72 is connected across the A.C. power source, and a load output terminals. The terminals are connected to electrodes 52 and 53. The power supply has no expensive adjustments as any adjustability of results in electrophoresis may be obtained by varying the time of application of the D.C. potential.

In operation, the device is assembled and the plate 44 is positioned with the electrophoresis supporting medium 45 thereon. The buffer solution 48 is placed in the separate chambers in container 26, and will be electrolytically connected to the supporting medium 45 by absorbent blocks 40 and 41. The composition to be separated in fractions, such as whole blood, blood serum,l or other materials having fractions which will migrate in an electric field, is placed on one end of the electrophoresis supporting medium 45 and the plug 57 may be connected to any suitable A.C. receptacle. The power pack steps down the voltage and rectifies the A.C. to supply the D.C. potential to electrodes 52 and 53 for a predetermined period of time to separate the substance into its various fractions for the purpose of separation, as is well known in the art of electrophoresis. The apparatus is then disassembled to the extent that plate 44 and electrophoresis supporting medium 45 and the separated fractions may be removed and examined. n this manner, the device operates in a manner well known in the art of electrophoresis, the invention residing in the particular construction affording a miniaturized unit of very simple construction and at extremely low cost which as the same time will be reliable for use in laboratory analysis.

While there have been shown, described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A micro-electrophoresis apparatus comprising;

(a) a single container including end and side walls and a divided bottom leaving a gap near the central portion of the bottom of the apparatus,

(b) an inverted U-shaped central dividing wall covering the gap in the bottom of the apparatus and dividing the inside of the container into two separate tanks adapted to contain liquid buffer solution;

(c) a pair of absorbent, sponge-like blocks, one positioned in each of the two separate tanks in the selfcontained unit,

(d) means dening a step integral with each of the sponge-like blocks at the top facing edges thereof for supporting a plate and an electrophoresis supporting medium so that the sponge-like blocks will establish electrolytic contact between the electrophoresis supporting medium and buffer solution in the separate tanks;

(e) a self-contained power supply positioned within the inverted U-shaped dividing wall,

(f) a circuit within the power supply for providing a constant potential direct current from a conventional alternating current source, and

(g) a pair of wire electrodes electrically connected to the power supply and extending through sealed openings in the inverted U-shaped dividing walls and positioned in the tanks adjacent thereto for supplying the electric current for the electrophoresis operation.

2. A micro-electrophoresis apparatus as defined in claim 1 wherein the circuit for the power supply is non-adjustable and includes a stepdown transformer and a rectifier.

3. A micro-electrophoresis apparatus as defined in claim 1 wherein the circuit for the power supply is non-adjustable and includes a voltage dropping resistor and a bridge rectifier.

4. A micro-electrophoresis apparatus comprising;

(a) a single container including end and side walls and a divided bottom leaving a gap near the central portion of the bottom of the apparatus,

(b) an inverted U-shaped central dividing wall covering the gap in the bottom of the apparatus and dividing the inside of the container into two separate tanks adapted to contain liquid buler solution.

(c) a pair of absorbent, sponge-like blocks, one positioned in each of the two separate tanks in the selfcontained unit, each sponge-like block having a height extending above the central dividing Wall and providing support for a plate and electrophoresis supporting medium on the plate so that the spongelike blocks will establish electrolytic contact between the electrophoretic supporting medium and buffer solution Within the separated tanks,

(d) a self-contained power supply positioned within the inverted U-shaped dividing wal-l,

(e) a circuit within the power supply for providing a constant potential direct current from a conventional alternating current source, and

(f) a pair of electrodes electrically connected to the power supply and extending through sealed openings in the inverted U-shaped dividing walls and positioned in the tanks adjacent thereto for supplying the electric current for the electrophoresis operation.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Block et al.: Paper Chromatography and Paper Electrophoresis, pp. 508-522, 1958.

Fox: Chemical Products, Apparatus for Chromatographie and Electrophoretic Analysis, pp. 260-266, July 1954.

Lederer: Chromatographic Review, vol. 3, 1961, pp.

Science, volume 120, p. 6A, July 2, 1954.

JOHN H. MACK, Primary Examiner.

25 JOHN R. SPECK, Examiner.

G. E. BATTIST, E. ZAGARELLA, Assistant Examiners. 

1. A MICRO-ELECTROPHORESIS APPARATUS COMPRISING (A) A SINGLE CONTAINER INCLUDING END AND SIDE WALLS AND A DIVIDED BOTTOM LEAVING A GAP NEAR THE CENTRAL PORTION OF THE BOTTOM OF THE APPARATUS (B) AN INVERTED U-SHAPED CENTRAL DIVIDING WALL COVERING THE GAP IN THE BOTTOM OF THE APPARATUS AND DIVIDING THE INSIDE OF THE CONTAINER INTO TWO SEPARATE TANKS ADAPTED TO CONTAIN LIQUID BUFFER SOLUTION; (C) A PARI OF ABSORBENT, SPONGE-LIKE BLOCKS, ONE POSITIONED IN EACH OF THE TWO SEPARATE TANKS IN THE SELFCONTAINED UNIT, (D) MEANS DEFINING A STEP INTEGRAL WITH EACH OF THE SPONGE-LIKE BLOCKS AT THE TOP FACING EDGES THEREOF FOR SUPPORTING A PLATE AND AN ELECTROPHORESIS SUPPORTING MEDIUM A PLATE AND AN ELECTROPHORESIS SUPPORTING MEDIUM SO THAT THE SPONGE-LIKE BLOCKS WILL ESTABLISH ELECTROLYTIC CONTACT BETWEEN THE ELECTROPHORESIS SUPPORTING MEDIUM AND BUFFER SOLUTION IN THE SEPARATE TANKS; (E) A SELF-CONTAINED POWER SUPPLY POSITIONED WITHIN THE INVERTED U-SHAPED DIVIDING WALL, (F) A CIRCUIT WITHIN THE POWER SUPPLY FOR PROVIDING A CONSTANT POTENTIAL DIRECT CURRENT FROM A CONVENTIONAL ALTERNATING CURRENT SOURCE, AND (G) A PAIR OF WIRE ELECTRODES ELECTRICALLY CONNECTED TO THE POWER SUPPLY AND EXTENDING THROUGH SEALED OPENINGS IN THE INVERTED U-SHPAED DIVIDING WALLS AND POSITIONED IN THE TANKS ADJACENT THERETO FOR SUPPLYING THE ELECTRIC CURRENT FOR THE ELECTROPHORESIS OPERATION. 